//Storage封装
const STORAGE_KEY='mall';
export default{
	setItem(key,value,module_name){
		if(module_name){
			let val=this.getItem(module_name);
			val[key]=value;
			this.setItem(module_name,val);
		}
		else{
		let val=this.getStorage();
		val[key]=value;
		window.sessionStorage.setItem(STORAGE_KEY,JSON.stringify(val));
		}
		

	},
	//获取某个模块下的属性，如user下面的username
	getItem(key,module_name){
		if(module_name){
			let val=this.getItem(module_name);
			if(val)
				return val[key];
		}
		return this.getStorage()[key];
	},
	getStorage(){
		return JSON.parse(window.sessionStorage.getItem('mall') || '{}');
	},
	clear(key,module_name){
		let val=this.getStorage();
		if(module_name){
			if(!val[module_name]) return;
			delete val[module_name][key];
		}
		else{
			delete val[key];
		}
		window.sessionStorage.setItem(STORAGE_KEY,JSON.stringify(val));


	}
}